Useful command in managing Active Directory

Here's some of the list that common to use on day to day administration and troubleshooting of Active Directory:

> To summarizes the replication state and health of a forest:
Repadmin /Replsum /BySrc /ByDst

> To show the state of the last inbound replication for specified domain controller:
Repadmin /Showreps
Repadmin /Showrepl

> To show the state of the last inbound and outbound replication (change notification) for specified domain controller:
Repadmin /Showrepl /repsto

> To display the replication queue list:
Repadmin /queue
> To display all the Domain Controller in the forest:
Repadmin /Viewlist *
> To display the Intersite Topology Generator (ISTG) server for specified site:
Repadmin /ISTG
> To display the Bridgeheads servers for specified site:
Repadmin / Bridgeheads

> To synchronize a sepecified domain controller with all of the replication partners
Repadmin /syncall (DC_name) /A /e

> To list the name of Domain Contollers in a domain:
Nltest /dclist:(domainname)

> To verify if we can locate a domain controller:
Nltest /dsgetdc:(domainname)

> To display the servers that hold FSMO role:
Netdom query FSMO

> To chek the health of DNS settings:
DCdiag /test:DNS

> To query the tombstonelifetime setting in a forest:
dsquery * "cn=Directory Service,cn=Windows NT,cn=Services,cn=Configuration,dc=contoso,dc=com" -scope base -attr tombstonelifetime